1. Field of the Invention
The invention relates to a toner image fixing device for fixing onto the recording material an unfixed toner image formed on recording material.
2. Description of the Related Art
In an image forming apparatus such as an electrophotographic copying machine, a printer and the like, as a toner image fixing device for fixing onto the recording material an unfixed toner image formed on recording material, so-called a heat roller system toner image fixing device is generally known and spread, which comprises a heat roller and a pressure roller that comes into pressure contact with the heat roller.
In the heat roller system toner image fixing device of this kind, in order to prevent toner offset, a parting agent is supplied onto a surface of the heat roller, so that such consideration is given that fixing quality of the toner image can be maintained.
Incidentally, in oils used as the parting agent, there is oil having volatile odor component. Mercaptan denatured silicon oil is representative of the oils used as the parting agent.
Though the mercaptan denatured silicon oil is superior in parting ability and heat stability, in case that the mercaptan denatured silicon oil is used under a temperature environment of about 170xc2x0 C. and more, an offensive odor is emitted in the surroundings, which gives an unpleasant feeling to a worker who is working there.
In spite of the generation of the above offensive odor, in the conventional toner image fixing device, surface temperature of the heat roller is generally set to 190xc2x0 C. and more. Therefore, careful consideration in relation to the problem of the offensive odor was not given.
Here, in case that the mercaptan denatured silicon oil of the predetermined capacity has been left as it is for twenty-four hours under the temperature environment of 190xc2x0 C., the volatile odor component of 0.5% and more in relation to the above predetermined capacity is generated. The value of xe2x80x9c0.5% and morexe2x80x9d corresponds to a rank of xe2x88x923 (very unpleasant) in pleasure/unpleasure degree display of nine ranks according to an evaluation method of odor in xe2x80x9cProgress and Results of Deodorization Technologyxe2x80x9d (P147) published by Comprehensive Technical Center Corp.
An object of the invention is to provide a toner image fixing device that can fix a toner image onto recording material very well by suppressing generation of a volatile odor component included in a parting agent without emitting an offensive odor in the surroundings an image forming apparatus , even if the parting agent including the volatile odor component is used.
In order to achieve the above object, a toner image fixing device comprises:
a first roller having a heater lamp provided therein;
a second roller coming into pressure contact with the first roller at a pressure contact portion;
a parting agent supplying unit adapted to supply a parting agent having a volatile odor component onto a surface of the first roller; and
an auxiliary heating unit provided on at least one side of an upstream side and a downstream side in a recording material transporting direction in relation to the pressure contact portion,
wherein a recording material having unfixed toner on a front surface thereof is heated and pressed at the pressure contact portion while being nipped and conveyed at the pressure contact portion, thereby fixing the unfixed toner onto the recording material; and
a surface temperature of the first roller is set to a temperature at which the volatile odor component has no more than a permissible value.